Subscriber-operated telephone system



UNiTED STATES? PATENT ,oFFicE.

FRANK M. swoon, or ROCHESTER, NEW YORKQASSIGNOR TO THE STROMBERG-CARL, son TELEPHONE MANUFACTURING, COMPANY, or noqHEsTER, N W YO A.

CORPORATION OF NEW YORK,

snnscmnnnornitarnn TELEPHONE SYSTEM,

Application filed January 28, 1918. Serial No. 214,057.

To all whom it may concern:

Be it known thatI, FRANK M. S oUoH, a citizen of the United States, residing at Rochester, inthe county of Monroe and State of New York, have invented certain new and useful Improvements 1n Subscriber Operated Telephone Systems, of

which the following is a full clear, and concise description.

This invention relates. to telephone systems in which automatic or electrically operated switches are employedrin establishing connections from calling to called lines.

The object of this invention is a provision" the line circuit to be made.

It has been found that in practice such improperoperation preliminary to the dialing operation by the subscriber occurs quite often, and causes the selective switches of the subscriber operated systems of the art heretofore used, to operate in other than the manner desired and causes them to make connection with other than the desired line whose number is sent by the subscribers dial under. the control of the subscriber.

It is a particular object of my invention to so arrange the apparatus at the central office of an automatic system that such improper interruptions of the line circuit occurring prior to the dialing operation and followed by the dialing operation will not operate the selective switches of the system in any but the'desired way to secure connection-with the desired line.

is a further object of my invention to accomplish the aforesaid object by simple changes in the first selector switch apparatus which can be applied to existing systems or which may be installed in automatic systems with minimum expense and complication.

The invention is illustrated in connection with a fast and slow automatic system so called, that is, in which fast and slow relays are operated underthegcontrol of subscribers instrument apparatus to control the operatlon of the selective switches in the de-.

sired manner.

The accompanying sheet ofdrawings diagrammatlcally lndicates theapparatus and circuits employed in the present embodiment The calling device indicated at .the substation of the 'subscribers of this invention.

line may be of any desired character, in which a-series of interruptions is produced in the line circuit. Many devices for accomplishing this result are well known and understood in the art. 7

Referring to the drawings, at A I show a callingsubstation having asendingdial 8 together with the usual talking and signaL ing apparatus connected by line conductors of the line leading to the central office equipment illustrated in'the drawing. While no nonnumeric al switch is shown for extending'the calling line to an idle first selector,

it willbe understood that any well-known,

form of line finder or line switch may be inserted at the point where the line conductors- In the are indicated by the broken'lines. event that a non-numerical switch is not employed the sub-station may be-connected di' rectly tothe line conductors of an idle first selector switch mechanism as is illustrated.

at S in the drawing; The selectorswitch mechanism contains a line relay 100, two slow relays 101 and 105 which are construct ed to release'their armatures slowly, such a construction being well known in the art,

an escape magnet'lOG controlling the operation of side switch wipers 114, 115, 116, 117

' Specification o'f Letters Patent. Patented S t 20 1921" 1' and 119. A primary stepping-magnet PM is indicated in the drawing to control the movementof the selector switch wipers 108,

109 and 110 to a group of sets of contacts, each set leading to a connectorswitch mechanism one of which is indicated in the drawing. A secondary switch magnet SM is illustrated in connection with the said first selector switch S, to advance the set of selectorwipers from'one set of contacts to another until contacts leading to an idle connector switch mechanism are located. The

selector switch apparatus also includes a set of contacts 206 comprising normally opened tion,"but which are moved to their operative positions after the primary stepping magnethas moved the selector switch wlpers a certain distance under the control of calling line substation apparatus. 7

To carry out the purposes of'my invention, I arrange the system of my invention so that the first digit of the number designating telephone lines to. be called, is increased one or more numbers; that is, if

vthe subscribers number would otherwise be 216, that in the system of my inventionsuch a telephone line would be numbered 316'or 1 416 depending. upon thejud'gment of the person employing my invention and the construction of the substation I hookswitch mechanism employed. Ifthe first digitis increased by: one numeral, provis on is thereby made for the correction of one false interruption of the line circuit'made by the subscriber pr or to operating his sender mechanism, and 1f the first digit is increased by two numerals provision is thereby made for the correction of one or two false inter ruptions of the line circuit by the calling subscriber in preparing to make a call.

'l-hus, by suitably altering the numbers of calledlines, and of course, suitably proportioning the apparatus 206, provision may be made for the correction pof'the required 7 7 number of false contacts made prior" to the a; succeeding train of interruptions properlysending or dialing operation. tus. of the first selector. switch. S is so arranged that if the first train of interruptions of the line circuit which is connectedto the first selector switch contains less than a given predetermined number of circuit interruptions, that the selector switch mechanismwill immediately restore to normal position and to such a condition as will permit produced to call a; called-telephone line to operate. the 'selector' switch mechanism to advance,ithe aforesaid object, whenever the number of interruptions of a continuous chain of interruptions contains more than the'predetermined number, this is taken to mean that the interruptions are properly produced and the selector switch mechanism after the predetermined number of inter-' .ruptionshave-been made will disable the said apparatus shown in the drawing- 206, so that it will be impotent to disable the said selector switch mechanism.

Although the connectorswitch forms no part. of this invention, it will he understood that the present invention may be used in any system having connector switches of any well-known typesuch as that disclosed on' page 44 of Automatic telephony by.

Smith and Campbell. I It is believed that the invention will now be readily understood from the description v of the manner in which the switches are controlled'in establishing a connection from The apparacalling to called telephone lines. The subscriber desiring zto make a call, will take his. receiver from the hook closing a circuit, in-

cludingthe substation instrument vand the hookswitch, and contacts 118. The closing switch, not shown infthe drawing but understood, to: interconnect. in any suitable way the line conductors leading to the substation A to side switch wipers 116 and. 117 of an idle first selector switch, which we will assume is the'selector switch S. This will complete a circuit including thecircuit conductors of the said line, .thesaidwipers 116 and 117 through the first position contacts of the side "switch through the windings of the line relay 100 of the first selector switch, the said circuit also including the central office source of current. Current from the said source will flow over the said circuit operating the relay 100, which will attract its armatures closing. contacts 20 1 and 202, the contacts 202 being closed for a purpose later to be described, and the contacts 20% closing a circuit for the operation of the slow relay 101; The relay 101 operattacts 203 fora purposelater to be described.

The relays 100 and 101 will open'contacts 201 and 205 respectively. 4

'The foregoing describes theoperation of certain apparatus'under the condition that the subscriber will properly remove his re- Ting-will attractits armature closing con ceiver from the hook, causing no false contacts or interruptions of the line circuit to bemade. I,

lVe will now assume that the subscriber improperly in taking his receiver from'the hook, causes one or two interruptions of the line circuit to. be made, followed by a continued closure of the line circuit preparatory for the dialing operation, At each interrupfor the time, off normal contact 104, magnet-.1 3, to'the negative pole of battery. The primary magnet 103, thus steps the switch carriage carrying the brushes 108, 109'and 110, toward. the banks-ofcontacts connected to trunksl ading to connector switches. As-

suming', however, that only'oneor two interruptions of'the line circuit are made with the construction ofthe switch 206 during this period, and at theend of this period the contacts ofthis' switch willreinain in the position shown in the drawing and will cause, at theend of the improper line in terruptiohs, a circuit to be completed for leasing relay 101, which remains energized i I I 70 of thesecontactswill cause. a non-numerical the release magnet 102 of the, selector switch" S, as will be described.

Following the improper interruptions and the restoring of the closed condition of the line clrcuit, the relay 105, after an interval retracts its armature, deenergizing the es-- cape magnet which thereupon releases the side switch into position 2.- The circuit of the secondary stepping magnet 107, would.

now be closed, were t not for the opened contacts 208 of the switch 206, which contacts remain open at this time due to the fact that an improper, and therefore insufiicient number of lin interruptions have been made, to cause the closure of these contacts 208 in the stepping circuit of the secondary magnet 107 which will under these conditions. remain unoperated, though the side switch wiper 114 otherwisemovlng into position 2, would complete an operative circuit for the said magnet. WVhen the relay 105 de'e'nergized, a circuit was therefore closed for the slow to operate release magnet 102 of the selector switch S, the saidrelease circuit including a conductor from the negative pole of the source, of current and the said release magnetl02, the off normal contacts 209, now closed, the side switch wiper 119, a second position contact there;

for, normal contacts 210 of the relay 105,

now restored,'still closed contacts 211 of the switch 206, now closed contacts 202 of the first selector line relay 100 to the ground pole of the source of current. Current from the said source will flow over the said circuit, operating the release magnet102- to restore the switch mechanism to normal pos1- tion shown in the drawing, the selector switch carriage being restored toits normal posit on, and the s de swltch wipers be ng restored to their normal position as shown.

in thetlrawing'. The line relay 100 h0wever, may remain in its operated position, as also the relay'controlled thereby, 101.

Now, the subscriber may by operating his dial in the propermanner, cause the proper operationof the selector switch as might have been done had nofalse or improper interruptions of the line circuit been made in preparing for the .diallng operation. Upon the'calllng subscr ber sending aproper Y series of impulses containing more than, say, two impulses, the armature of line re lay 100 will vibrate,;and upon each retraction of the armature, an lmpulse is trans mitted over the circuit previously traced for, the said primary stepping magnet 103 of the first selector S, causing the prlmary stepping magnet 103 to step the brushes into operative relation of the desired. group of trunks. This operation beingmore extended I than the before described improper'operation, the switch 206 will be moved from its normal position to a position in which'the contacts 211 for the release magnet are opened, so that the release magnet will not be operated after the first series of impulses have been received, and the contacts 208 thereof will be closed inv the'circuit of the secondary stepping magnet '107. Therefore, when the sender s restores and maintains the line circuit closed the relay 105, retracting its armature after an interval and there by deenergizing the escape magnet which causes the release of the side switch to position 2, causes a circuit to be completed for the secondary magnet 107, the said circuit being traced as follows: i From the ground pole of the source of current, the now closed contacts 204; of the first selector line relay 100, the side switch wiper 114 and second position contacts therefor, now closed con- 'tacts 208 of the switch 206, normal contacts tion. In positi0n2, the escape magnet 106 is connected to the test brush 110 over side switch arm'115. When the test brushencounters a grounded multiple 113, it becomes energized to release'the side switch into position 3, the side switch arm 114 in passing out-of position 2 opening the;circuit of the secondary stepping magnet r107 -thus stopping the selector upon the seized trunk. 1 r i At the termination of a call when the subscriber at A replaces his receiver on the switchhook, the connector switch C is released in the well-known manner and again applies ground'to test terminal 113. This is effective to cause the energization of the release magnet 102m a clrcuit extending from grounded battery, winding of this magnet, primary ofi-normal contacts 209,

side switch wiper 119 in its third position,

test brushllO to ground at test terminal 113. The release magnet 102 when operated accomplishes the release of the selector switch in the manner well known, g I I'amaware that other forms of switching apparatus may be employedto carry out my invention than that specifically illustrated in the embodiment thereof which has been described. lam also aware that the switching'apparatus 206 may in suitable form be 1 made a part of a switch operatedprior to the selector switch apparatus, such as an intermediate line finding or trunkfindingswitch for interconnecting a calling line with a first selectorswitch. Other numerous and extensive departures maybe made from the of an i'ncomingline, a plurality of outgoing lines, a switch mechanism for interconnecting said incoming line with any of said outgoing lines switch wipers for the said switch 1 mechanism,- primary moving means to move the said switch in a primary (lHQCiJIOII, secg ondary moving means to 'HlOVG the said switch wipers in a secondary direction, a sub station sending dial for the said incoming line adapted to control the extent of movement of the said switch wipers by the primary switch wiper. moving rheansfautomatically operated means to move the said switch wipers in a secondary direction, and

' means responsive only to a given degree of movement of the switch wipers under the control of the said substation sending dial ,for, conditioning" said secondary switch wiper'moving means for operation but effectiveafter a predetermined primary movement of said switch wipers to prevent said the said switch wipers'in a primary direce tion, secondary moving means to move the secondary switch wiper movingmeans from operating.

2. In a telephone system, the combination of an incoming line, a plurality of outgoing lines, a switch mechanism for interconnecting said incoming line with any of said outgoing lines, switch wipers for the said switch mechanism, primary moving means to move said switch wipers in a secondary direction, a sub-station sending dial for the said incoming line adapted to control the extent of movement of the saidswitchwipers by the primary switch wiper moving means automatically operated means to move the said'switchwipers in a secondary directioin; slow operating means operative when the movement of thesaid switch wipers in'a' primary direction is discontinued under'tlie' control of said'sub-stationsending dial, and a release mechanism for the said switch mechanism, said release mechanism being operated under the control of the said slow operating means, only on less than a given degree of primary, movement of the said switch wipers.

3. Ina telephone system, :thecombination' of an incoming line, a plurality oioutgoing lines, a switch mechanism for interconnecting said incoming line with any of SitldOut going lines, switch wipers for the said move the said switch wipers in a primary manner, secondary moving means to move the said switch wipers'ina secondary manmeans from operating. I

ner', asub-stationsending dialfor the said incoming line adapted to control the extent of movement of thesaid switch wipers-by the primary switch wiper moving -means, automatically operated means" to move the "said switch wipers in a secondary manner,

and means responsive to a given degree of movement of the-si'vitch' w pers under the control of the said substation sending dial- 'for cond tioning said secondary switchwi'per moving means foroperation, but effective after'a predetermined movement of said switch wipers in a primary direction toprevent said'secondary, switch wiper moving at. In a telephone system,- the combination of an'incoming'line', a {plurality of outgoing 'linespa switch mechanism for 'interconnecting said incoming line with'any of said outgoing lines, switch wipers for the r said switch mechanism, primary moving means to move the said switch wipers n a primary manner to select trunk groups, see ondary moving means to .move the said switch wipers in a secondary manner to select a given trunk in a group, a sub-station sending dial for the said incoming line adapted to control the extent of movement of the said switch wiper-s1 by the primary sw tch wiper moving means, automatically operated means to move the said switch wipers in a secondary mannerto select trunk 7 groups, and means responsive only to a given degree of 'moven'ient' of the said switch wipers under thecontrol of thesaid 'substation sending dial for conditioning said sec ondary switch wiper movingineansfof op;-

eration, but effectiveafter a predetermined switch wiper moving'means' from operating. 5. In a'telephone system, the combination of an incoming line,' a plurality of outgoing lines, a switch mechanism for nterconnecting said incoming line with any of said outgoing lines, switch wipers for. the said sw tch mechanism, primary moving means to move the said switch wipers in a'primary tomatically operatedmeans to' move the said switch wipers ina secondary direction, slow v operating means operative when the movement/of the 'sa'idaswitch wipers inapri mai'y' direction is discontinued under the p control ofsaid sub-station sending dial, and switch mechanism, primary movingmeans to" a release mechanism for the said switch mechanism, said release mechanism being "'movement of said switch wipers in a pri- ,mary direction to prevent said secondary degree of primary movement of the said switch wipers. Y

' 6. In a telephone system, the combination of an incoming line, a plurality of outgoing lines, a switch mechanism for interconnecting said incoming line with any of dial for the said incoming lineadapted to control the extent of movement of the said switch wipers by the primary switch wiper moving means, automatically operated means to move the said switch wipers'in a secondary direction, slow operating means operative when the movement of the said switch wipers in a primary direction is discontinued under the control of said substation sending dial, and a release mechanism for the said switch mechanism, said release mechanism being operated under the control of the said slow operating means, only on less than a given degree ofpri'mary movement of the said switch wipers.

7. In a telephone system, the combination of an incoming'line, a plurality of outgoing lines, a switch mechanism for interconnectmg said incoming line'with any of said outgoing lines, switch wipers for the said switch mechanism, primary moving means to move the said switch wipers in a primary direction, secondary moving'means to move the sald switch wipers 111 a secondary direction,

a sub-station sending dial forthe said iii-- coming line adapted to control the extent of movement of the said switch wipers by the primary switch wiperw moving means, automatically operated means to move the sald switch wipers in a sec-c ondary direction, slow operating means operative when the movement of the said switch wipers in a primary direction is discontinued'under the control of said sub-Sta tion sending dial, a release mechanism for the said switch mechanism, said release mechanism being operated under the control of the said slow operating means, only on less than a given degree of primary movement ofthe said switch wipers, disabling means for the said secondary switch wiper moving means, and means to disable the said disabling means responsive only to a given degree of primary movement of the said switch wipers.

8. In an automatic telephone system, the combination of a first selector switch, primary stepping means for the said switch, secondary stepping means for the said switch, disabling means for the said secondary stepping means, and a secondary disabling means for the said firstnamed disabling means, said second disabling means being responsive to a 'plurality of switch stepsunder the control or the switch stepping meansr Y e 9. In an automatictelephonesystemfthe combination of a firstselector switch, a stepby-step primary magnet for the said switch, a step-by-step secondary magnetfor the'sai'd switch, a substation sending dial for controlling the primary movement of the said said primary switch, automatic apparatus for controlling the secondary movement of'the said switch,

said automatic apparatus being responsive to operate the said switch to'theend'ofa first switch operation under the control of the said substation sending dial,-and 'disabling means for the said secondaryStep by-step moving means, said disabling -me'ans being disabled under the control of means operated after a given number of switch steps under the control of saidsubstation sending dial.

' 10. In. a telephone system,the combination *of a calling telephone line, substation apparatus for the said line, circuit closing means for the said substation apparatus, a selective switch capable of moving primarily to select trunk groups, and secondarily to select trunks of a group adapted to be operated under-the control of the said substation apparatus, primary magnet for primarily moving the said selective switch, a secondary magnet for secondarily moving the" said switch, means responsive to a given number or line circuit closures by the said substae tion apparatus to advance the said switch to connect the calling line with a given trunk of a selected group under the control ofjthe said-primary "and secondary magnets, and

disabling means for the said switch. responsive to the last closure of less than a predetermined number of circuit closures to restore the said switch to normal.

11. In a telephone system, the combination of a calling telephone line, substation apparatus for the said line, circuit closing means for the said substation apparatus, a selective switch capable of moving primarily to select trunk groups, and secondarily to select trunks of a group adapted to be operated under the control of the said substation apparatus, a primary magnet for primarily moving the said selective switch, a secondary magnet for secondarily 'moving the said switch, means responsive to a given number of line circuit closures by the said substation apparatus to advance the said switch to connect the calling line with a given trunk ofva selected group under the control of the said primary and secondary magnets, and disabling means for the said switch responsive to the last closure of less than a predetermined number of circuit closures to restore the said switch to normal, 7

of a, calling telephone line, substation appas.

ratus for the said line, circuit closing means for the said substation apparatus, a selective switch capable of moving primarily to select trunk 'groups, and secondarily, to select trunks of a group adapted to be operated under the control of the said substationapparatus, a primary magnet for primarily moving the said selective switch, a secondary magnet; for secondarily moving the said switch, means responsive to. a given number of line circuit .closures by the said substation apparatus to advance the said switch to connect the calling-line with a. given trunk.

ofa selected group underthe'control of the saidprimary and secondary magnets, and

' disabling means for the said switch responsive to thelast closure of less than a prede- J termined .number'of circuit closures to restore thefsaid switch to normal, said disa bling means comprising means'for preventing the operation of the said switch by the said secondary magnet. V

13. In a signal'ng system, the combination with aselective switch, ofa circuit inter rupter and a source of current, a magnet controlling the motion of the said selective switch, means to include the said magnet,

' the said source of current and the said circuit interrupter in acir'cuit, whereby the said circuit interrupter may control the op eration of the said switch, a second controlling means for the said switch, a .second interrupting device :in circuit with the first} named circuit interrupter, and. means ,to

cause. the second controlling means to restore the said selective switch to its normal position whenever the said switch is operated to less than a predetermined degree untomatic switch having off normal contacts arranged to-be closed only after a p're -determined number ofsteps, means for advancing said switch, an impulse relayprovided with,

contacts and operated oversaid incoming circuit to control said advancmgmeans, a release magnet for said switch and a'circuit for said release magnet completedthrough I said off-normal contacts and ofjsaid impulse relay. H i

15. In an automatic telephone system, an

front contacts incoming circuit, a plurality of outgoing circuits, an automatic step by:step switch'for' inter-connecting said incom ngv circuit with any of said outgoing circuits, said automatic switch having normally open and normally closed sets of ofi-normal contacts, the conditions of which is reversed after a predetermined number of steps by said switch, a primary motor magnet for directively controlling said switch in its :primary movements, a secondary motor magnet foradvancing said switchtoan idle outgoing circuit, a release magnet for releasing said switch and circuitsfor saidrelease magnet and for said secondary motor magnetcontrolled through said off-normal contacts. M

I In witness'whereof, I hereunto'subscribe my name this 25th day of January, .A. D.

FRANK sLoUGH} 

